Trend AnalysisOther Engineering
Additive Manufacturing of Metals: From Laser Powder Bed Fusion to High-Entropy Alloys
Metal additive manufacturing via laser powder bed fusion is pushing into new alloy systems and post-processing techniques. Recent work on high-entropy alloys and advanced steels demonstrates both the expanding design freedom and the persistent metallurgical challenges that define this field.
By Sean K.S. Shin
This blog summarizes research trends based on published paper abstracts. Specific numbers or findings may contain inaccuracies. For scholarly rigor, always consult the original papers cited in each post.
Metal additive manufacturing (AM) has moved well beyond prototyping. Aerospace, medical, and automotive industries now rely on laser powder bed fusion (L-PBF) for production parts with geometries impossible to achieve through traditional machining or casting. The technology deposits thin layers of metal powder and selectively melts them with a high-power laser, building components layer by layer with micron-scale precision.
Yet metal AM faces stubborn challenges: residual stresses from rapid solidification, microstructural defects like porosity and columnar grain growth, and the need for post-processing to achieve the mechanical properties demanded by engineering applications. The latest research pushes on all three fronts simultaneously.
Why It Matters
The global metal AM market exceeded $5 billion in 2024 and is projected to double by 2028. Industries that need lightweight, complex geometry parts---turbine blades, orthopedic implants, rocket engine components---are betting on L-PBF as a core production technology. But expanding from established materials (Ti-6Al-4V, Inconel 718) to new alloy systems requires understanding how AM's unique thermal history affects microstructure and performance.
The Research Landscape
High-Entropy Alloys via L-PBF
Liang and Sun (2025) investigate the FeCoNiCrMn high-entropy alloy (HEA) fabricated by L-PBF, examining how post-build heat treatment can mitigate the microstructural defects inherent to the process. HEAs---alloys with five or more principal elements in near-equimolar ratios---offer exceptional combinations of strength, ductility, and corrosion resistance. Their study reveals that targeted heat treatment can dissolve the columnar dendritic structures typical of L-PBF while reducing residual stress, though controlling grain growth remains delicate.
Process Parameter Optimization for Structural Steels
Kublinska and Sulowski (2025) systematically map how laser power, scan speed, and layer thickness affect the metallurgical and mechanical properties of 25CrMo4 steel. This chromium-molybdenum steel is widely used in automotive and structural applications. Their parameter study identifies the processing window that minimizes porosity while achieving target hardness and tensile strength---critical data for qualifying AM parts in safety-critical applications.
Surface Engineering for AM Parts
recent studies, with 3 citations, demonstrate that plasma-assisted duplex surface treatment can significantly enhance the scratch resistance of 17-4 PH stainless steel produced by L-PBF. This finding addresses a key limitation: AM parts often have inferior surface properties compared to wrought equivalents. The duplex treatment (nitriding plus physical vapor deposition coating) creates a hard surface layer without compromising the bulk mechanical properties.
Comprehensive Technology Review
Khan, Afzal, and colleagues (2024), with 2 citations, provide a broad review of powder bed fusion techniques, cataloguing the current state of the art across electron beam and laser-based systems, material capabilities, and remaining gaps in process reliability and certification standards.
Key Comparison: AM Process Parameters and Outcomes
<
| Parameter | Effect on Density | Effect on Strength | Trade-off |
|---|
| Higher laser power | Increases (better melting) | Increases (fewer defects) | Risk of keyholing, spatter |
| Faster scan speed | Decreases (incomplete fusion) | Decreases | Higher throughput |
| Thinner layers | Increases | Increases | Slower build, higher cost |
| Post-build heat treatment | No change | Can increase or decrease | Grain growth vs. stress relief |
What To Watch
The convergence of high-entropy alloys and metal AM is a frontier with enormous potential---HEAs offer properties unachievable with conventional alloys, and AM offers the geometric freedom to exploit them. Expect rapid progress in computational tools that predict AM microstructure from process parameters, reducing the expensive trial-and-error cycles that currently dominate new alloy qualification.
Metal additive manufacturing (AM) has moved well beyond prototyping. Aerospace, medical, and automotive industries now rely on laser powder bed fusion (L-PBF) for production parts with geometries impossible to achieve through traditional machining or casting. The technology deposits thin layers of metal powder and selectively melts them with a high-power laser, building components layer by layer with micron-scale precision.
Yet metal AM faces stubborn challenges: residual stresses from rapid solidification, microstructural defects like porosity and columnar grain growth, and the need for post-processing to achieve the mechanical properties demanded by engineering applications. The latest research pushes on all three fronts simultaneously.
Why It Matters
The global metal AM market exceeded $5 billion in 2024 and is projected to double by 2028. Industries that need lightweight, complex geometry parts---turbine blades, orthopedic implants, rocket engine components---are betting on L-PBF as a core production technology. But expanding from established materials (Ti-6Al-4V, Inconel 718) to new alloy systems requires understanding how AM's unique thermal history affects microstructure and performance.
The Research Landscape
High-Entropy Alloys via L-PBF
Liang and Sun (2025) investigate the FeCoNiCrMn high-entropy alloy (HEA) fabricated by L-PBF, examining how post-build heat treatment can mitigate the microstructural defects inherent to the process. HEAs---alloys with five or more principal elements in near-equimolar ratios---offer exceptional combinations of strength, ductility, and corrosion resistance. Their study reveals that targeted heat treatment can dissolve the columnar dendritic structures typical of L-PBF while reducing residual stress, though controlling grain growth remains delicate.
Process Parameter Optimization for Structural Steels
Kublinska and Sulowski (2025) systematically map how laser power, scan speed, and layer thickness affect the metallurgical and mechanical properties of 25CrMo4 steel. This chromium-molybdenum steel is widely used in automotive and structural applications. Their parameter study identifies the processing window that minimizes porosity while achieving target hardness and tensile strength---critical data for qualifying AM parts in safety-critical applications.
Surface Engineering for AM Parts
recent studies, with 3 citations, demonstrate that plasma-assisted duplex surface treatment can significantly enhance the scratch resistance of 17-4 PH stainless steel produced by L-PBF. This finding addresses a key limitation: AM parts often have inferior surface properties compared to wrought equivalents. The duplex treatment (nitriding plus physical vapor deposition coating) creates a hard surface layer without compromising the bulk mechanical properties.
Comprehensive Technology Review
Khan, Afzal, and colleagues (2024), with 2 citations, provide a broad review of powder bed fusion techniques, cataloguing the current state of the art across electron beam and laser-based systems, material capabilities, and remaining gaps in process reliability and certification standards.
Key Comparison: AM Process Parameters and Outcomes
<
| Parameter | Effect on Density | Effect on Strength | Trade-off |
|---|
| Higher laser power | Increases (better melting) | Increases (fewer defects) | Risk of keyholing, spatter |
| Faster scan speed | Decreases (incomplete fusion) | Decreases | Higher throughput |
| Thinner layers | Increases | Increases | Slower build, higher cost |
| Post-build heat treatment | No change | Can increase or decrease | Grain growth vs. stress relief |
What To Watch
The convergence of high-entropy alloys and metal AM is a frontier with enormous potential---HEAs offer properties unachievable with conventional alloys, and AM offers the geometric freedom to exploit them. Expect rapid progress in computational tools that predict AM microstructure from process parameters, reducing the expensive trial-and-error cycles that currently dominate new alloy qualification.
References (5)
[1] Liang, J., Zhu, G., & Sun, J. (2025). Influence of Heat Treatment on the Microstructure and Mechanical Properties of FeCoNiCrMn High-Entropy Alloy Manufactured via Laser Powder Bed Fusion. Metals.
[2] Kublinska, A., Dzienniak, D., & Sulowski, M. (2025). Laser Powder Bed Fusion of 25CrMo4 Steel: Effect of Process Parameters on Metallurgical and Mechanical Properties. Materials.
[3] Khan, R., Afzal, M., et al. (2024). Powder Bed Fusion Techniques in Metal 3D Printing: A Review. Key Engineering Materials.
[4] Gomez-Ortega, A., et al. (2024). The Scratch Resistance of a Plasma-Assisted DUPLEX-Treated 17-4 PH Stainless Steel Additively Manufactured by LPBF. Coatings.
Gรณmez-Ortega, A., Pinilla-Bedoya, J. A., Ortega-Portilla, C., Fรฉlix-Martรญnez, C., Mondragรณn-Rodrรญguez, G. C., Espinosa-Arbelรกez, D. G., et al. (2024). The Scratch Resistance of a Plasma-Assisted DUPLEX-Treated 17-4 Precipitation-Hardened Stainless Steel Additively Manufactured by Laser Powder Bed Fusion. Coatings, 14(5), 605.